A lot of great points. I've worked with a lot of people that know one language well but are almost willfully ignorant to others... even when the skills are needed on the current projects. I've gotten to where when I interview applicants I worry less if they know the answer to esoteric questions about rarely used features of certain languages and spend more time on architecture, testing/debugging and deployments. It's amazing how many people interview with 15 years of Java but no experience with Continuous Integration and testing techniques beyond JUnit.